This study is a prospective cohort study to evaluate the peripheral blood lymphocyte subsets as predicative biomarkers reflecting the efficacy and toxicity in patients with locally advanced non-small cell lung cancer (NSCLC) received chemoradiotherapy (CRT) with or without immune checkpoint inhibitors (ICIs).

All patients had a pathologically confirmed locally advanced NSCLC according to the 8th AJCC staging system and received definitive radiotherapy, concurrently or sequentially combined with platinum-based doublet chemotherapy. The peripheral blood samples at various time points including before radiation, 4 weeks after beginning of radiation, the end of radiation, 1 month post radiation, and 1 month post consolidation immunotherapy were collected for lymphocyte subsets detection.

The subjects will be divided into two groups according to whether patients received ICIs, namely, NSCLC patients received CRT plus ICIs and NSCLC patients received CRT.

Inclusion Criteria:

1. Age 18-75 years; ECOG score 0-2.
2. Pathologically confirmed locally advanced NSCLC according to the 8th AJCC staging system.
3. Received definitive radiotherapy, concurrently or sequentially combined with platinum-based doublet chemotherapy.
4. No serious medical diseases and dysfunction of major organs, such as blood routine, liver, kidney, heart and lung function.

Exclusion Criteria:

1. Pathologic type was adenocarcinoma with EGFR gene mutation or ALK gene rearrangement.
2. Patients with other active malignancies within 5 years or at the same time.
3. Active or previously documented autoimmune or inflammatory diseases (including inflammatory bowel disease, diverticulitis [except diverticular disease], systemic lupus erythematosus, Sarcoidosis syndrome, Wegener' s syndrome).
4. History of allogeneic organ transplantation.
5. History of active primary immunodeficiency.
6. Patients with uncontrolled concurrent diseases, including but not limited to persistent or active infection (including tuberculosis, hepatitis B, hepatitis C, human immunodeficiency virus, etc.), symptomatic congestive heart failure, uncontrolled hypertension, unstable angina pectoris, uncontrolled arrhythmia, active interstitial lung disease, severe chronic gastrointestinal disease with diarrhea or mental illness.
7. Women of child-bearing potential who are pregnant or breastfeeding.
8. The investigator judged other situations not suitable for inclusion in this study.

Consecutive locally advanced NSCLC patients treated with definitive CRT with or without ICIs at hospital.